1. Field of the Invention
The present invention relates to a method for controlling reproduction speed of an optical disk that is suitable to an optical disk apparatus such as a CD-ROM driver for reproducing recorded data and transmitting it to a connected instrument through a digital interface.
2. Description of the Background Art
Construction and operation of an optical disk apparatus for reading and reproducing a data recorded in an optical disk such as a CD or a CD-ROM and transmitting it to a personal computer (PC) connected thereto through a digital interface will now be described with reference to the accompanying drawings, especially, taking an example of a CD-ROM driver that reads and reproduces a data recorded in a CD-ROM at a high speed for transmission and a personal computer (PC) that is connected to the CD-ROM driver through a digital interface to receive the data therefrom.
FIG. 1 is a schematic view showing a connection between an optical disk apparatus, i.e., a CD-ROM driver, and a personal computer (PC) in accordance with a conventional art.
As shown in the drawing, the CD-ROM driver includes an optical pick-up (P/U) 2 for reading a data recorded in an optical disk such as a CD-ROM; a wave filtering/shaping unit 3 for filtering a signal read by the optical pick-up 2 and outputting it as an RF (radio frequency) signal; a digital signal processing (DSP) unit 4 for processing the RF signal to be a digital signal; a buffer 5 for temporarily storing the processed digital signal; an interface (I/F) unit 6 for transmitting the output signal of the digital signal processing unit 4 or the digital signal temporarily stored in the buffer 5 to a connected personal computer; a servo/driver 7 for varying the rotation speed of the optical disk 1 and the data reading position of the optical pick-up 2; and a MICROCOMPUTER 8 for outputting a control signal corresponding to a key input by a user.
The personal computer receives the digital signal, that is, a data, transmitted through the interface unit 6 as well as transmitting and receiving a control signal (Hold, Ready) for controlling operations of the MICROCOMPUTER.
Data transmission by the CD-ROM driver xe2x80x98Cxe2x80x99 connected through the digital interface and corresponding reproducing operation will now be described with reference to FIG. 2.
FIG. 2 is a flow chart of data transmission between the conventional optical disk apparatus and the personal computer and a corresponding operation, which, especially, is a flow chart of transmission of a data read and reproduced from the CD-ROM driver xe2x80x98Cxe2x80x99 to the personal computer 20 connected through the digital interface unit, and a corresponding reproducing operation of the CD-ROM driver.
First, with reference to FIG. 1, a data recorded in the optical disk 1 is read by the optical pick-up 2 and then converted into an RF signal, that is, a high frequency signal, by the wave filtering/shaping unit 3 so as to be inputted to the digital signal processing unit 4. Then, the digital signal processing unit 4 processes the RF signal to be a digital signal and temporarily stores it in the buffer 5 (S10).
Thereafter, the digital signal, that is, a data, temporarily stored in the buffer 5 is transmitted to the personal computer 20 connected through the interface 6 (S11). At this time, the data processing speed for reading and storing the data, that is, the reproduction speed, is as fast as it can be increased to 48 times speed at its maximum, whereas, the transmission speed of transmitting a data to the personal computer 20 through the interface 6 is as low as one time speed or two times speed in case of a real time data such as a motion picture data.
Therefore, in case that the reproduction speed of the CD-ROM driver is as high as 48 times speed, the personal computer 20 transmits a control signal (Hold, xe2x80x981xe2x80x99) instructing to temporarily stop data transmission to the MICROCOMPUTER 8 of the CD-ROM driver through the interface unit 6.
Upon receipt of the temporary stoppage control signal (Hold, xe2x80x981xe2x80x99) (S12), the MICROCOMPUTER 8 controls in a manner that the data transmission operation is stopped (S13) and controls the operation of the servo/driver 7 so that the data reading operation of the optical pick-up 2 is in pause (S14).
The temporary stoppage of data reading operation is made by a tracking operation in which track jumping is repeatedly performed so as for the optical pick-up 2 to repeatedly search the same recording operation in a state that the optical disk 1 is being rotated at a high speed.
Thereafter, when a control signal (Ready, xe2x80x980xe2x80x99) instructing a resumption of data transmission is transmitted to the MICROCOMPUTER 8 through the interface unit 6 (S15), the MICROCOMPUTER 8 releases the data reading temporary pause (Pause) mode of a current operation mode (S16) and controls the operation of the servo/driver 7 so that the data reading operation is resumed by the optical pick-up 2.
At this time, a recording position of a corresponding optical disk 1 is searched at the time point when the reading operation was temporarily stopped, to perform data reading operation from the corresponding recording position. And then, data reading, storing and transmitting operations are repeatedly performed until the completion of reproducing (S17) in the same manner as stated above.
Accordingly, data transmission between the CD-ROM driver that reads, stores and transmits the data recorded in the optical disk 1 at a high speed and the personal computer 20 that receives and processes the data at a low speed.
However, due to the speed difference between the data reading speed in the CD-ROM driver and the data receiving speed of the personal computer 20, data reading pausing and releasing operations should be repeatedly performed, which requires an accurate track jumping operation or searching operation.
In addition, in case that track jumping operation and searching operation are not made accurately and quickly, the buffer for temporarily storing the transmission data is short of data, resulting in that an output image comes to a pause temporarily or a noise image such as a flicker is outputted.
Therefore, an object of the present invention is to provide a method for controlling reproduction speed of an optical disk in which when a data recorded in an optical disk recorded in an optical is read, stored and transmitted to a connected instrument through a digital interface, the speed in reading and reproducing the data recorded in the optical disk is controlled to be varied at a high speed or at a low speed according to a transmission rate or a residual amount of the stored data.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a method for controlling reproduction speed of an optical disk including: a first step of reproducing a data recorded in an optical disk and storing it; a second step of externally transmitting the stored data through a digital interface; and a third step of varying the data reproduction speed of the optical disk according to the transmission rate of the data.
In order to achieve the above object, there is also provided a method for controlling reproduction speed of an optical disk including: a first step of reproducing a data recorded in an optical disk and storing it; a second step of externally transmitting the stored data through a digital interface; and a third step of monitoring a residual amount of the stored data, and varying the reproduction speed of the data of the optical disk if the residual amount of the stored data exceeds a reference value.